Hi and welcome. I married a guy who was very understanding and patient while we were dating. I guess my best advice is to go at her pace and maybe ask questions gently on occassion. That is what my husband did for me.
I did not talk much about Crohns before I met him. He asked questions when he could tell I was in a good frame of mind and left me alone when I pushed back. His questions were not about the gory details, but more like "does it hurt all of the time or most of the time" or "how do you know what to do when you feel lousy". I credit him for making me able to talk about my disease which has in turn made it a lot easier to deal with. He was not overly concerned or helpful acting which I am sure would have pushed me away (I had a guy who tried to wait on me and "solve" everything or make everything better and I could not stand it).
Now I am on this website and I go to a CCFA support group (where I have made some good friends!). 13 years later, he still does not really understand everything, but he also knows he doesn't always get it and that helps.
Maybe you could show her this site or print out your post here. Just let her work on her pace.
Good luck and thanks for being a caring person!